Fluids based on fluorocarbon compounds are widely used in vapour compression heat transfer systems, in particular air conditioning, heat pump, refrigeration or freezing devices. These devices have in common the fact that they are based on a thermodynamic cycle comprising the vaporization of the fluid at low pressure (in which the fluid absorbs heat); the compression of the vapourized fluid up to a high pressure; the condensation of the vapourized fluid to liquid at high pressure (in which the fluid releases heat); and the expansion of the fluid in order to complete the cycle.
The choice of a heat transfer fluid (which may be a pure compound or a mixture of compounds) is dictated, on the one hand, by the thermodynamic properties of the fluid and, on the other hand, by additional constraints. Thus, one particularly important criterion is that of the impact of the fluid considered on the environment. In particular, chlorinated compounds (chlorofluorocarbons and hydrochlorofluorocarbons) have the disadvantage of damaging the ozone layer. Henceforth, generally non-chlorinated compounds such as hydrofluorocarbons, fluoroethers and fluoroolefins are therefore preferred to them.
It is however, necessary to develop other heat transfer fluids that have a global warming potential (GWP) lower than that of the heat transfer fluids currently used, and that have equivalent or improved performances.
The use of ammonia as a heat transfer fluid is known. However, a certain number of problems are associated with this compound: a very high compressor outlet temperature compared to hydrofluorocarbons; an absence of oil return and the necessity to install an oil separator; a permitted total charge that is sometimes limited due to the toxicity of the product.
Document WO 2007/126414 describes a large number of mixtures of heat transfer compounds, and in particular mixtures comprising 2,3,3,3-tetrafluoropropene (HFO-1234yf) and ammonia. The only compositions specifically disclosed in this document and that comprise these two compounds are quaternary compositions comprising two additional compounds, namely difluoromethane (HFC-32) and pentafluoroethane (HFC-125), or else HFC-32 and trifluoroiodomethane.
Document WO 2008/009928 describes heat transfer compositions based on pentafluoropropene, tetrafluoropropene and at least one additional compound, which may be ammonia.
Document WO 2008/009922 describes heat transfer compositions based on 1,2,3,3,3-pentafluoropropene (HFO-1225ye) and which may comprise, in certain embodiments, HFO-1234yf or ammonia.
Document US 2006/0243945 describes a large number of mixtures of heat transfer compounds, and in particular mixtures comprising HFO-1234yf and at least one other compound chosen from a list of compounds including ammonia. The only compositions specifically disclosed in this document and that comprise these two compounds are quaternary compositions comprising two additional compounds, namely HFC-32 and trifluoroiodomethane.
However, there is still a need to develop other heat transfer fluids that have a relatively low GWP and that are capable of replacing the customary heat transfer fluids.
In particular, it is desirable to develop other heat transfer fluids with a low GWP that are quasi-azeotropic or even azeotropic and/or which have good energy performances relative to customary heat transfer fluids (such as R404A or R410A).